Coaxial feedline varmint repellent ?

[K1JJ]

I wonder if anyone has experience with this problem...

I just put up a new Beverage and had to run the RG-59/U coaxial cable on the ground in the woods.  I tried elevating the feedline, but it caused some common mode issues.

With past Beverages during the winters, animals ate through the coax at least every two months. I don't want to buy RG-6 direct bury stuff cuz I needed 500' and had the RG-59/U available - plus, I have a 500' relay control cable running with the coax. I'd rather not put it in PVC pipe nor bury it naked.

Can anyone recommend some kind of repellent that can be applied to the coax?  Something with the consistency of grease might stay on for a few months at a time, if it worked.  

I did a scan on Google and this forum and see nothing related to feedline repellents, but didn't look into repellents in general yet.

Suggestions?  (No, I don't want to stand guard out there with a 22 varmint rifle all winter)

T

[k4kyv]

Is the primary of your coupling transformer totally isolated from the  secondary?  That is, two separate windings, not an autoformer, and the coax to the transformer should not be  grounded at the far end.  The secondary winding and coax should float. Maybe even a choke balun between the near end of the coax and the receiver.

Check the common mode pick-up by disconnecting the coax at the far end and temporarily terminating it with a carbon resistor that matches Zo of the coax. You should hear nothing in the receiver but background hiss.

I have found that critters will chew even on "direct burial" coax.  I passed up a 1000' roll of direct burial RG-6 at Dayton last year because I have about given up on buried cable.  My beverage coax just lies on the ground, and I have to occasionally repair animal damage.  Some of them make cuts that look like someone sliced it with a razor.  I was beginning to wonder if it was critters or vandals, but I have a  lot  more stuff round here that would be more attractive to vandals than a piece of coax running across the field.  I just tape up the damaged spots every year.  I haven't noticed enough loss to make any perceptible difference in reception after several years of repeatedly repairing the coax.

[K1JJ]

Is the primary of your coupling transformer totally isolated from the  secondary?  That is, two separate windings, not an autoformer, and the coax to the transformer should not be  grounded at the far end.  The secondary winding and coax should float. Maybe even a choke balun between the near end of the coax and the receiver.

Check the common mode pick-up by disconnecting the coax at the far end and temporarily terminating it with a carbon resistor that matches Zo of the coax. You should hear nothing in the receiver but background hiss.

Yes, I did isolate the coax using a separate primary and sec - and grounded the sec only. The coax floats. I also added a choke balun at the feedpoint, in the middle of the run and also added a choke and ground rod about 20' from the feedpoint as suggested by ON4UN and HUZman.

The coax when disconnected is quiet with no hiss or signals.   The system seems acceptable now that the coax runs along the ground.


It seems when the critters bite into the coax, water will wick in and contaminate the coax more than just at the bite area. After a few years, my old coax was full of splices and bite marks.

Well, I'll sit tight and see if anyone has a suggestion. I might look into general repellents too.

T

[Tom WA3KLR]

Hi Tomas,

There's a line of products called Shake-away.  I had trouble here with a groundhog chewing through the phone line where it enters the house underground. I bought a bag of Shake-away groundhog repellent which is dried fox urine; seems to work.   This is the time of year when they start to rejuvenate their hibernation tunnels.

I don't know what critter likes your coax, but maybe Shake-Away has something useful.  I have a few coaxes buried just under the grass here, no problems.

[N8ETQ]

   DOG


[/quote]

I wonder if anyone has experience with this problem...

Suggestions?  (No, I don't want to stand guard out there with a 22 varmint rifle all winter)

T
[/quote]

[Bill, KD0HG]

Dog fur.

After brushing out the pup, save the fur and sprinkle it along the feedline.

Or switch to a run of surplus CATV aluminum jacket hardline.

[KL7OF]

Tom...I have never had any critter problems with coax as long as it stays above ground...as soon as I bury it, the pocket gophers get it........I tried putting poison grain in the trench with the cable and even gave it a personal urine treatment to no avail....Now I use pvc pipe where the cablesmust be buried where it crosses my road.....I wind transformers for my beverages with separate pri and sec and let the coax float...I haven't used a choke balun at the feedpoint or a ground rod/choke 20 ft from the feedpoint...With the coax disconnected from the beverage, the coax doesn't act as a snake antenna...Do you think I can get added performance by adding a balun and a chokeground?

Sorry I don't have an answer to your critter chewing problem...any idea what the critters are? Gud Luk...Steve

[K1JJ]

Bill,

Yes, CATV is critter-proof and a good idea. I could even use RF chokes and run the DC control voltage on the hardline. I now run 600' of CATV hardline underground up to the doghouse in 4" PVC pipe. The total run to the Bev is about 1100' including the RG-59U.  If I had 500' of CATV I would try that and get rid of the PVC control cable too. Maybe next year.


Tom, thanks for the Shake-Away tip. I did some reading on Amazon of the reviews and it seems mixed. But there's not much else out there it seems. I still wonder if a light greasing of the whole run wud work? Or maybe it wud attract them more...


T

[K1JJ]

Tom...I have never had any critter problems with coax as long as it stays above ground...as soon as I bury it, the pocket gophers get it........I tried putting poison grain in the trench with the cable and even gave it a personal urine treatment to no avail....Now I use pvc pipe where the cablesmust be buried where it crosses my road.....I wind transformers for my beverages with separate pri and sec and let the coax float...I haven't used a choke balun at the feedpoint or a ground rod/choke 20 ft from the feedpoint...With the coax disconnected from the beverage, the coax doesn't act as a snake antenna...Do you think I can get added performance by adding a balun and a chokeground?

Sorry I don't have an answer to your critter chewing problem...any idea what the critters are? Gud Luk...Steve

Hi Steve,

I think since your coax is on the ground level you should be OK. Actually, I still have some of my coax elevated, so that may be my problem, dunno.  My f-b is good with DX but very poor for locals (high angle) - so I'm thinking I have some common mode issues. My other Bevs had a better local f-b.

If your ant pattern is good with a nice all-around f-b, you should be OK. I added the chokes and extra gnd rod in an attempt to run the WHOLE coax run elevated. But so far I  dropped a section nearest the Beverage on the ground - thus the request for varmint protection. If I come up with something good, I will drop the whole run on the ground. Bill's idea of using CATV alum cable (and RF chokes for the DC) is really the best idea.

That 3/4" gray electrical PVC pipe you buy at Home Despot wud work too. It's only about $1.80/ 10' section, so cheap enuff for a few hundred foot run to protect the coax and control lines.

** I guess what I'm really wondering is can a feedline that's 6' above the ground, 70' away from the Bev affect its performance? It runs almost parallel. I thought a bev was so closely coupled to the ground that anything even 20' away was invisible, unlike a conventional dipole, etc. The Bev is 550' long and 6' -7'  off the ground.

T

[W2VW]

Dried blood. Garden centers sell it. Keeps veggie eating varmints away. Maybe they think coax is a veggie.

[K1JJ]

Dried blood. Garden centers sell it. Keeps veggie eating varmints away. Maybe they think coax is a veggie.

Makes sense - Halloween, Dracula.

I'll bet it's mice having a ball under the snow in their tunnels. They usually go thru the PVC and then hit the copper and drop it like a hot potato. But other critters have cut the coax in two and just left it like that.

Back about ten years ago, I had the Bev run in a different area. Stray hunters come thru sometimes. One day the Bev wire was on the ground with small pit marks all over it. I couldn't understand how a squirrel could have gotten up on the wire at 6' and chewed it. Turns out it was hit by a frustrated hunter with shotgun...

T

[k4kyv]

A number of years ago a ham had a beverage running across his private property. Some lady decided to go horseback riding through the field, without asking permission, didn't see the wire and was knocked off her horse as it ran under the antenna.  She filed suit against the landowner/antenna owner for damages.

[KA2DZT]

Tom,

Allow me to suggest the liberal use of peanut butter on the cable.  The peanut butter will attract all the nearby elephants.  The elephants, as big as they are, will scare all the small critters away from eating your coax.

Sounds like a solid plan of attack,  should work.

Hope this helps,
Fred

PS,  I'll keep you posted if I think of any more good ideas.

[Ed/KB1HYS]

slathering the cable in the stickiest grease you can find might work. but you'd have to use something like cosmoline else it will just wick into the soil around the cable. 

I think the conduit idea is probably the most sure-fire way to go.

You could keep some HVDC onthe shield when not in use, then they'd only chew it once...

[KM1H]

I had quad shield and flooded RG-6 and 11 destroyed between October and January about 20 years ago and went with .412 CATV hardline for the 750' run. That size was obsolete even then and I got a full reel plus some connectors for free. A case of beer is considered free

Elevating feedlines destroys the effectiveness of the Beverages here, chokes were no help. The feedline passes under the 160M radials as well as close to guy wires.  Also isolate the transformer ground leads. I have a ground rod right below the transformer box for the antenna ground and another rod 20' away with a clamp over an exposed part of hardline shield and covered with automotive undercoat spray. I also run the relay control voltage thru the coax.

Carl

[k4kyv]

Flexible conduit can be made from that black plastic water line.  Don't remember exactly what they call it, but it comes in rolls, in standard water pipe sizes up to 1 1/2" or more.  I saw some recently at Lowe's and it wasn't too expensive.  I have several rolls of used stock that I pulled from the dump.

I suspect that buried conduit eventually becomes full of water even if it is well sealed, due to condensation, unless a positive pressure of dry air or nitrogen is kept on the line, as in the case of heliax.  If you use direct burial coax the water shouldn't matter as long as it is undamaged, but the plastic pipe should protect the wire from critters. I used direct burial power cable to get electricity from the house to the shack, and put mine in regular PVC conduit made for the purpose.  It is buried deeply enough that conduit should not have been necessary, but I am always digging around here and it would have been too easy to damage the cable if I accidentally dug into it.  Also, where the cable enters and exits the ground would be a prime  target for rodents.

I don't think they actually eat the jacket because they are hungry.  Rodents have an urge to chew on things and the plastic seems to satisfy them nicely. Chewing is necessary to keep their teeth, which continue to grow, from becoming too long. A rat or mouse kept in a cage with no access to anything to chew on will eventually be injured or disabled by excessive tooth growth.

[K1JJ]

Good info, thanks.


Looks like I'll drop the whole 500' run on the ground based on your experience of chokes not helping elevated feedlines, Carl.

The plastic water pipe is a cheap and interesting alternative, Don.  One way to thread a long pipe like that is to put a small plastic bag attached to a thin string on one end and then pull it thru the other side using a vacuum cleaner. We did that here for an underground 240AC run once.

I'll try running the RG-59/U and control cable without protection this season and then look for some CATV hardline using DC control RF chokes for next year.  In the meantime, we'll see how many times I try the NE Bev this season and find it dead...

T

[W1RKW]

Tom,
This isn't practical so I don't recommend it for 500' of cable run but I used to keep the critters away from bird feeders by greasing up the poles with a mixture of crisco vegetable shorting and tabasco.  To watch the squirrels lick their little mitts of the mixture and start jumping and squirming all over the place was quite the spectacle.

[WA1GFZ]

About 300 VDC on the shield when you are not using the antenna Current limited of course.

[Ed/KB1HYS]

Just a thought, but couldn't you just bury it a bit deeper?  I'm thinking that moles or critters would only be a foot or so max depth.  Put it down as deep as you can. Filling the trench with gravel (1" size or so) might also discourage burrowers.

[Bill, KD0HG]

Flexible conduit can be made from that black plastic water line.  Don't remember exactly what they call it, but it comes in rolls, in standard water pipe sizes up to 1 1/2" or more. 

I use that stuff in 1/2" size for drip irrigation of trees and the veggie garden.

Critters chew through it all the time. Maybe they're after the water inside. They bite through it like a knife. I have to splice it every year.

[W9GT]

Tom,
This isn't practical so I don't recommend it for 500' of cable run but I used to keep the critters away from bird feeders by greasing up the poles with a mixture of crisco vegetable shorting and tabasco.  To watch the squirrels lick their little mitts of the mixture and start jumping and squirming all over the place was quite the spectacle.

As I noted in previous posts...have had lots of problems with squirrels eating my vehicles' wiring, as well as my antenna coax feed lines.  I have used a product called Critter Ridder, which apparently contains something like pepper spray.  We sprayed it around our vehicles and it apparently discourages the varmits.  It, however, is expensive and washes away with rain...so you have to re-apply...might be something to try anyway.  Squirrels might be cute...but they are very destructive...just ask the power and phone companies.

73,  Jack, W9GT